1. Field of the Invention
The presently disclosed instrumentalities pertain to a hazard warning device for aircraft. In particular, the device provides warnings that may be heeded to mitigate problems of engine roll back and sensor blockage due high ice crystal concentrations, together with problems of erosion and subsequent damage to aircraft surfaces. This protects also engine turbine blades from extended encounters with dust and volcanic ash.
2. Description of the Related Art
High concentrations of airborne particles present a hazard to aviation. These particles, especially water droplets, ice crystals, dust particles or volcanic ash particles, may contribute to such major problems as accidents and loss of life. The particles may also cause costly damage to aircraft parts. Aircraft at this time have no systems for detecting when they are encountering these particles other than visual observations by the flight crew.
Commercial aircraft are equipped with forward looking radar systems for detecting precipitation-sized cloud particles that allow them to avoid regions with hail, lightning and other cloud phenomenon that could be hazardous for flight operations. These radar operate at a wavelength that is sensitive to hydrometeors larger than 100 μm, but cannot detect regions where there are very high ice crystal concentrations since these types of crystals are typically much smaller than 100 μm. Likewise, dust and ash particles are much smaller than 100 μm and cannot be detected by the aircraft weather radar system. Potentially hazardous dust and ash particles are found in thin layers that cannot be observed by the flight crew from below or above and are only visible when looking through them horizontally due to their optical thickness. When these layers are embedded in clouds, they are impossible to discern by eye.
Other than the weather radar, commercial aircraft are equipped with no other sensor capable of measuring the characteristics of cloud, dust and ash particles and hence have no way of recognizing when the aircraft is within potentially hazardous conditions.